Glass reflecting-mirror.



110 797,455. PATENTED AUG..15,1905. G, A. PARS0N$ & Gm STONEY. GLASSREPLEUTING MIRROR.

APPLICATION FILED HAY26. 1903.

3 SHEBTB-QHEBT 1.

manna a 02mm co. PncTu-u'mocmmzns, wAsmucmu. n c.

m0. 797,455. PATENTED AUG.15, 1905.

G. A PAB$0N$ & G. G. STONEY. GLASS RBFLEGTING MIRROR.

APPLIOATION FILED MAYZG. 1903.

BSHEETS-SHEBT 2.

N0 797,455. PATENTED AUG. 15., 1905.

G. STONEY.

GLASS REFLEGTING MIRROR.

G. A. PARSONS (33 G APPLICATION FILED EILYZB. 1903.

f u, U 2 AZ aw W 2 .W 0%

WWW

lunnw. B. GRAHAM co, PmYO-LIIWORAPMRB. wmmnuvon, u c.

nrrEn STATES errinn'tr omuon.

CHARLES ALGERNON PARSONS AND GEORGE GERALD STONEY, ()FNEWUASTLE-UPON-TYN E, ENGLAND; SAID STlONEY ASSIGNOR TO SAID PARSONS.

no. vet/ass.

@pecification of Letters Patent.

Patented Aug. 15, 1905.

Application filed May 26,1903. Serial No. 158,904.

To (all whom it 'nm/y concern.-

Be it known that we, (humans ALeERNoN PARSONS and GEORGE GERALD SToNEY,subjects of the King of Great Britain and Ireland, and residents ofHeaton Works, Newcastleupon-Tyne, in the county of N orthumberland,

England, have invented certain new and useful improvements in GlassReflecting-Mirrors, (for which we have made application for LettersPatent in Great Britain, N 0. 22,938, dated October 21, 1902,) of whichthe following is a specification.

Our invention relates to glass reflectingmirrors, such as are used forsearch-light projectors, and has for its object to mount such mirrors ina more secure and protected manner than hitherto and also to cool themirrors in such a way as to keep down the temperature even when they areplaced near the most powerful electric are.

We have discovered that by placing a conducting-surface in closeproximity to the back of the mirror the transference of heat from themirror to the backing is very rapid, and if the conducting-surface iskept cool by any efficient means the mirror will also be kept cool;also, if a thin layer of paper, asbestos, or other similar material beplaced between the back of the mirror and the conductingsurface thecooling of the mirror is not seriously decreased.

Our invention therefore consists in mounting a mirror for such purposesas search-light projectors in close proximity to a backing made of agood conductor with or without a thin sheet of paper or other materialplaced between the backing and the mirror, the backing being cooled inany suitable manner.

Referring to the accompanying drawings, which illustrate our invention,Figure 1 shows the invention applied to a search -light in which themirror is cooled by water. Fig. 2 shows a vertical section, drawn to anenlarged scale, of the mirror and backing which is cooled by air. Fig. 3shows an elevation of a portion of the backing of the mirror shown inFig. 2. Fig. 4C is a section through a mirror in which the cooling iseli'ected by shot or other granular material contained. in the pocketsat the back of the mirror.

lln carrying our invention into effect according to one modification weconstruct the glass reflector a in any well-known manner and provide abacking 7), formed of a casting of aluminium or other material machinedto the form of a hollow cup, curved so as to lit closely to the back ofthe Inirror a, either in direct contact with it or with a thin layer ofpaper, asbestos, or other material (see Fi 4:) be tween them, so as toprevent the paint which protects the silver on the mirror a sticking tothe metallic backing Z).

The backing may be cooled by any wellknown method, such as gills or ribs0, attached to or forming part of the backing Z) to increase theradiating-surface or the circulation of air, water, or other liquid, orby the use of acetate of soda or other crystals having considerablelatent heat of fusion.

The mirror (0 may be secured and held close to the backing by spring orclips or by a ring (Z, Fig. 2, which may have a packing of woodite,asbestos, or other material a to prevent the access of moisture betweenthe mirror and the backing or by any other suitable well-known means.

The backing shown in Fig. 1 is cooled by a water-jacket 21, connectedwith the watersupply in the tank 7" by the circulating-pipes g it.

Small pockets a may be formed in the backing and filled with conductingmaterial on, as shown in Fig. L. The conducting material may be shot,aluminium granules, or the like, or masses of conducting material, suchas very firm hard metal, may be placed between the backing and themirror. A thin uniform sheet 0, of any suitable elastic substance, isinserted between the mirror and the backing or any of the meansdescribed above. This thin sheet protects the paint at the back of themirror, and it consists of a material such that it will readily give upits heat to the conductors provided for the cooling of the mirror.

Having now described our invention, what we claim as new, and desire tosecure by Letters Patent, is----- 1. in combination with a reflecting--mirror, a metallic plate litted in close proximity to the back oi themirror and means in rear of said plate for keeping said plate and mirrorcool.

2. in combination with a reflecting-mirror, a metallic plate litted inclose proximity to the back of the mirror, a thin sheet of protectingmaterial placed between the metal In Witness whereof Wehave hereunto setour backing and the mirror and means for keephands in presence of twoWitnesses.

111%; tlie backlng-plate and mirror cool. CHARLES ALGERNON PARSONS.

. n comblnatlon With a reflectmg-mn r01, GEORGE GERAID STOYEY a metallicplate fitted in close proximity to J t the back thereof, an inclosedspace behind lVit-nesses: said plate and a cooling medium in said spaceHENRY GRAHAM DAKYNS, J 111:, for keepingthe backing-plate and mll'lOlcool. WILLIAM MENZIEs JOHNSTON.

